JP2001125383A - Wet image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet image forming device capable of preventing liquid developer from being discarded or leaked at the time of performing maintenance service for a developing device. SOLUTION: After a carrying pump 34 is reversely rotated to restore the liquid developer 1 of a developing part 21 to an adjusting tank 30, the developing part 21, a developing roller 22 and a developer recovery part 23 are separated and detached from a developing unit 13, whereby the liquid developer 1 is prevented from being discarded or leaked at the time of maintenance. At the time of forming an image, the concentration and the amount of the liquid developer 1 stored in the tank 30 are controlled based on the detected result by a concentration detection means and a liquid amount detection means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet image forming apparatus such as a copying machine, a facsimile, a printer, and the like. More specifically, the present invention relates to a method for forming an electrostatic latent image formed on an image carrier into a liquid formed by a developing device. The present invention relates to a wet image forming apparatus that transfers an image developed by a thin layer of developer and visualized to a recording medium.

[0002]

2. Description of the Related Art Conventionally, as a developing device of this type of wet image forming apparatus, Japanese Patent Application Laid-Open No. Hei 7-244433 discloses a developing device in which a developing roller and a liquid supply means for the developing roller are provided in a liquid storage means. A device in which a roller, a liquid supply unit, and a liquid storage unit are integrated is disclosed.

FIG. 9 shows one embodiment of the developing device.
As shown in FIG. 1, a tank 2 serving as a storage means for storing the liquid developer 1, a supply means 3 disposed soaked in the liquid developer 1 stored in the tank 2, a developing roller 4, a regulating blade 5 and a scraping blade 6.

The supply means 3 includes a pair of gear rolls 8 and 9 having substantially the same length as the developing roller 4, and a pair of gear rolls 8 and 9.
And a case 10 that covers the tank 2 by rotating the gear-shaped roll pairs 8 and 9 in opposite directions.
Is pumped up and supplied to the developing roller 4. The liquid developer 1 supplied to the developing roller 4 is
After the thickness of the layer is adjusted by the regulating blade 5, the layer contacts the electrostatic latent image forming drum 7 to develop and visualize the electrostatic latent image on the electrostatic latent image forming drum 7. The liquid developer 1 on the electrostatic latent image forming drum 7 that has not been used for development is scraped off by the scraping blade 6. The tank 2, the supply means 3, the developing roller 4, the regulating blade 5, and the scraping blade 6 are provided in one cartridge, and can be replaced at a time. Further, the developing roller 4 and
Each of the electrostatic latent image forming drums 7 is rotationally driven by a driving device (not shown).

[0005]

However, in the developing device having the above structure, since the developing device is integrally formed, all the liquid developer in the developing device must be discarded at the time of maintenance service such as trouble or maintenance. There was a problem that did not become. Further, there is a problem that the liquid developer leaks when the developing device is removed from the apparatus main body.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a wet image forming apparatus capable of preventing liquid developer from being discarded or leaked during maintenance service of a developing device. It is to be.

[0007]

In order to achieve the above object, according to the present invention, an electrostatic latent image formed on an image carrier is formed by a thin liquid developer layer formed by a developing device. In a wet image forming apparatus that develops and transfers a visualized image to a recording medium, the developing device includes a developing unit provided with a developer carrier that supplies a thin liquid developer layer to the image carrier. A developer carrier cleaning unit that removes and collects the liquid developer on the developer carrier after development, and a liquid developer accommodating unit that can accommodate the liquid developer of the developing unit. The developing unit can be separated from other parts of the developing device.

In this wet image forming apparatus, when the developing section is maintained, after the liquid developer of the developing section is stored in the developer storing section and emptied, the developing section is moved to another developing apparatus. Separate from part and remove. Thus, it is possible to prevent the liquid developer in the developing unit from being discarded or leaked due to maintenance.

According to a second aspect of the present invention, in the wet image forming apparatus of the first aspect, means for supplying a liquid developer from the liquid developer container to the developing unit, and the liquid developer container from the developing unit And means for returning the liquid developer to the liquid developer.

In this wet image forming apparatus, at the time of image formation, development is performed by supplying a liquid developer from the liquid developer storage section to the developing section. During maintenance of the developing unit, the liquid developer in the developing unit is returned to the liquid developer storage unit and emptied.

According to a third aspect of the present invention, in the liquid image forming apparatus according to the first or second aspect, a liquid developer supply means for supplying a new liquid developer to the liquid developer storage section; A carrier liquid supply unit for supplying a new carrier liquid; and a transport unit for transporting the recovered liquid developer removed and recovered by the developer carrier cleaning unit to the liquid developer storage unit. is there.

In this wet image forming apparatus, when a high-density, high-viscosity liquid developer is used, the solid content concentration of the liquid developer gradually increases with the image formation unless the liquid developer or the carrier liquid is supplied. It tends to be up. This is because a small amount of the carrier liquid adheres to the image carrier other than the image area, so that the consumption of the carrier liquid is larger than the solid content. Therefore, when the solid content concentration of the liquid developer becomes high, the carrier liquid is replenished to lower the concentration and adjust to a predetermined concentration. When the liquid amount of the liquid developer decreases, the liquid developer is replenished and adjusted to a predetermined liquid amount.

According to a fourth aspect of the present invention, in the wet image forming apparatus of the first, second or third aspect, the apparatus further comprises a density detecting means for detecting a density of the liquid developer stored in the liquid developer storing section. It is assumed that.

In this wet type image forming apparatus, the concentration detecting means detects the solid concentration of the liquid developer in the liquid developer accommodating section. Therefore, based on the detection result,
It is possible to adjust the concentration of the liquid developer in the liquid developer container to a predetermined concentration.

According to a fifth aspect of the present invention, in the wet image forming apparatus of the fourth aspect, the density detecting means irradiates the thin liquid developer with light and measures reflected light or transmitted light of the light. It is characterized by the following.

In this wet image forming apparatus, the liquid developer thin layer is irradiated with light, and the amount of light reflected from the liquid developer thin layer or the amount of light transmitted through the liquid developer thin layer is transmitted. The light amount is measured to detect the density.

According to a sixth aspect of the present invention, in the wet image forming apparatus of the third, fourth or fifth aspect, there is provided a re-dispersion means for re-dispersing the recovered liquid developer in the liquid developer storage section. It is.

In this wet image forming apparatus, the collected liquid developer is redispersed to eliminate the solidified state of the collected liquid developer. The use of a liquid developer containing an agglomerated solid content deteriorates the resolving power. However, by resolving the agglomerated state by the redispersing means, the resolving power can be prevented from deteriorating.

According to a seventh aspect of the present invention, in the wet image forming apparatus of the sixth aspect, the redispersing means circulates the liquid developer by a pump.

In this wet image forming apparatus, the liquid developer in the liquid developer container is constantly circulated and dispersed by the pump to be redispersed.
The precipitation state of the solid content of the liquid developer is also eliminated. Thereby, it is possible to prevent the resolution from being deteriorated.

According to an eighth aspect of the present invention, in the wet image forming apparatus of the sixth aspect, the re-dispersing means agitates the liquid developer by a stirring blade provided in the liquid developer accommodating portion. Is what you do.

In this wet image forming apparatus, the liquid developer in the liquid developer storage section is constantly circulated and dispersed by the stirring blades to be redispersed, and the solidified state of the liquid developer is also eliminated. I do. Thereby, it is possible to prevent the resolution from being deteriorated.

According to a ninth aspect of the present invention, in the wet image forming apparatus of the eighth aspect, the internal shape of the liquid developer accommodating portion is:
It is characterized in that it is formed in a shape along the orbit slightly outside the rotation orbit of the tip of the stirring blade.

In this wet image forming apparatus, the inner shape of the liquid developer container is formed to be slightly outside the rotation orbit of the tip of the stirring blade and along the orbit.
The gap between the tip of the stirring blade and the inner wall surface can be reduced, so that the liquid developer pool can be eliminated. This allows
The liquid developer can be stirred and re-dispersed even if the rotation speed of the stirring blade is lower than a shape in which a liquid pool easily occurs, for example, a rectangular or elliptical internal shape.

The invention according to claim 10 is the invention according to claims 1, 2, 3,
The liquid image forming apparatus according to any one of 4, 5, 6, 7, 8 and 9, further comprising a liquid amount detecting means for detecting a liquid amount of the liquid developer stored in the liquid developer storing section. is there.

In this wet image forming apparatus, the liquid amount detecting means detects the liquid developer liquid amount in the liquid developer storage section. Therefore, based on the detection result, it is possible to adjust the amount of the liquid developer in the liquid developer container to a predetermined amount.

[0027] According to an eleventh aspect of the present invention, in the wet image forming apparatus of the tenth aspect, the liquid amount detecting means includes a light emitting element and a light receiving element disposed opposite to each other on a side wall of the liquid developer container. Wherein the presence or absence of the liquid developer on the optical path is detected by the amount of transmitted light of the light emitted from the light emitting element and reaching the light receiving portion through the inside of the liquid developer accommodating portion. It is assumed that.

In this wet image forming apparatus, when a liquid developer is present on the optical path between the light emitting element and the light receiving element, light emitted from the light emitting element is blocked by the liquid developer and the light The transmitted light amount of light reaching the element is reduced.
Conversely, when the liquid developer does not exist on the optical path, the amount of light transmitted from the light emitting element to the light receiving element without being blocked by the liquid developer becomes large. The presence or absence of the liquid developer on the optical path is detected based on the difference in the amount of transmitted light reaching the light receiving element.

According to a twelfth aspect of the present invention, in the wet image forming apparatus of the tenth aspect, the liquid amount detecting means emits light toward the liquid developer liquid surface, and emits light from the light emitting element. It is possible to receive light in a predetermined range corresponding to the height of the liquid developer liquid level to which the light reflected by the liquid developer liquid surface can reach, and to detect a specific light receiving position within the range. A light receiving device capable of measuring the displacement of the liquid level of the liquid developer based on the light receiving position detected by the light receiving device.

In this wet image forming apparatus, the displacement of the level of the liquid developer is detected by applying triangulation. Light emitted from the light emitting element is applied to the liquid developer liquid surface. Then, the light reflected from the liquid developer liquid surface is received at a predetermined position of the light receiving device according to the height of the liquid developer liquid surface. Since the light receiving position also moves each time the level of the liquid developer liquid level changes, the distance to the liquid developer liquid surface, that is, the level change of the liquid developer liquid level is detected by detecting the light receiving position. The amount can be detected. Here, a semiconductor laser or L
An ED light source can be used, and a light position detecting element (PSD), a charge transfer element (CCD), or the like can be used as the light receiving device.

The invention of claim 13 is the invention of claim 11 or 12
In the wet image forming apparatus, the liquid amount detecting means detects at least a lower limit liquid amount, a standard liquid amount, and an upper limit liquid amount of the liquid developer.

In this wet image forming apparatus, the liquid amount detecting means determines which one of the lower limit liquid amount, the standard liquid amount, and the upper limit liquid amount is the liquid developer liquid amount in the liquid developer storage section. Is detected. When it is detected that the liquid developer liquid amount has fallen below the lower limit liquid amount, the liquid developer is supplied, and when it is detected that the liquid developer amount has reached the standard liquid amount, the supply is stopped.
Thereby, the liquid amount of the liquid developer can be maintained at the standard liquid amount. Further, when it is detected that the liquid developer liquid amount is equal to or more than the upper limit liquid amount, it is possible to issue an overflow warning.

According to a fourteenth aspect of the present invention, in the wet image forming apparatus according to the thirteenth aspect, when the liquid amount detecting means determines that the liquid developer liquid amount in the liquid developer storage section has fallen below a lower limit liquid amount. The liquid developer is supplied to the standard liquid amount by the liquid developer supply means, and when the concentration detection means determines that the liquid developer concentration in the liquid developer storage section exceeds the reference concentration, The carrier liquid is supplied by a liquid supply means.

In this wet image forming apparatus, when it is determined by the liquid amount detecting means that the liquid developer liquid amount in the liquid developer storage section has fallen below the lower limit liquid amount, the liquid developer supplying means controls the standard amount. The liquid developer is supplied up to the liquid amount, and the carrier liquid is supplied by the carrier liquid supply unit when the concentration detection unit determines that the liquid developer concentration in the liquid developer storage section exceeds the reference concentration. The liquid developer in the liquid developer container is adjusted so as to have a predetermined liquid amount and a predetermined concentration. Thus, a liquid developer having a predetermined concentration can be constantly supplied to the developing unit.

According to a fifteenth aspect of the present invention,
In the wet-type image forming apparatus of 12, 13, or 14, the inner surface of the liquid developer accommodating portion is subjected to an oil-repellent treatment.

In this wet image forming apparatus, since the inner surface of the liquid developer accommodating portion is subjected to the oil repelling treatment, the liquid developer is prevented from adhering to the inner surface. In particular, it is possible to prevent erroneous detection due to the liquid developer adhering to the inner surface of the detecting section of the liquid amount detecting means. That is, if the liquid developer adheres to the inner surface of the detection unit, the light is blocked and the amount of transmitted light reaching the light receiving element is reduced, and the liquid developer is not present on the optical path even though the liquid developer is not present. May be erroneously detected, or the amount of reflected light reaching the light receiving element may be small, resulting in a detection error. These erroneous detections can be prevented by applying an oil-repellent treatment to the inner surface of the detection unit so that the liquid developer does not adhere thereto.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An embodiment in which the present invention is applied to a wet electrophotographic copying machine (hereinafter simply referred to as "copier") as a wet image forming apparatus will be described. First, an outline of the copying machine according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of a main part of a copying machine according to the present embodiment.

A charging unit 12, a developing unit 13, an intermediate transfer member 14, a photosensitive drum cleaning unit 15 and the like are arranged around a photosensitive drum 11 as a latent image carrier. Further, a transfer roller 17 is provided as a transfer unit for transferring the developed image to a transfer paper 16 as a final transfer material, facing the intermediate transfer body 14.

In the above configuration, the photosensitive drum 11 is driven to rotate at a constant speed in the direction of the arrow at the time of copying by a driving means such as a motor (not shown). After being uniformly charged in the dark by the charging unit 12,
The optical writing unit (not shown) irradiates and forms the writing light LB on the basis of the image information to form an electrostatic latent image on the photosensitive drum 1.
1 is formed. Then, the electrostatic latent image is developed by the developing unit 13, and an image is formed on the photosensitive drum 11. The image formed on the photoconductor drum 11 is transferred onto an intermediate transfer body 14 that is driven at the same speed as the photoconductor drum 11. The image on the intermediate transfer body 14 is transferred to a transfer paper 16 transported from a paper feed cassette (not shown) to a transfer unit.
Is transferred by the transfer roller 17. After the transfer, the transfer paper 16 is fixed by a fixing unit (not shown) and is discharged. The liquid developer 1 on the photoconductor drum 11 that has not been transferred onto the intermediate transfer body 14 is removed from the photoconductor drum 11 by the photoconductor drum cleaning unit 15. The remaining liquid developer on the intermediate transfer member 14 is removed by an intermediate transfer belt cleaning unit (not shown). After that, the residual potential of the surface of the photosensitive drum 11 is removed by a discharging lamp (not shown) to prepare for the next copy.

As shown in FIG. 1, the developing unit 13 in the copying machine of the present embodiment includes a developing section 21, a developing roller 22, a developer collecting section 23, and a developer accommodating section (hereinafter, referred to as a developer accommodating section).
A "developer adjusting unit" 18) and a toner bottle 19
And a carrier bottle 20. The liquid developer 1 used in the present embodiment has a viscosity of 1
In the range of 00 to 10000 mPa · s, the toner concentration is 5
A material having a range of 40% is used. More specifically, for example, one having a viscosity of 300 mPa · s and a toner concentration of 15% is used. The developing unit 21 includes a storage tank 24 storing the liquid developer 1, an application roller 25 that applies the liquid developer 1 to the development roller 22, and a pair of screws 26 a that supply the liquid developer 1 to the application roller 25. , 26b, and a regulating blade 27 for regulating the amount of the liquid developer 1 on the surface of the application roller 25. Storage tank 24 is 10
0 to 150 cc of the liquid developer 1 can be stored. When the pair of screws 26a and 26b are driven, the liquid level of the liquid developer 1 in the storage tank 24 rises,
When the raised portion comes into contact with the application roller 25, the liquid developer 1 is supplied to the application roller 25. The amount of the liquid developer 1 supplied to the application roller 25 is regulated by the regulating blade 27, and about 30 cc of the liquid developer 1 is applied to the development roller 22 per minute. Developer collection unit 2
3 is a scraping roller 28 and a cleaning blade 29
, And mainly cleans the liquid developer 1 remaining on the surface of the developing roller 22.

In the developing unit 13 of the copying machine according to the present embodiment, of the components of the developing unit 13, the developing unit 21, the developing roller 22, and the developer collecting unit 2
Numeral 3 is provided in one cartridge (a portion surrounded by a dashed line in the figure), and this cartridge can be removed from the main body of the copying machine when maintenance or replacement is performed. When the cartridge is separated from the developing unit 13 and detached from the copying machine main body, the transporting pump 34 of the developer adjusting unit 18 is rotated in the reverse direction to remove the liquid developer 1 in the storage tank 24 from the adjusting tank 30.
And empty the storage tank 24. Then, the drain cock 36 provided in the pipe portion between the transport pump 34 and the storage tank 24 is closed, and the connection of the coupling 37 is released, whereby the coupling can be removed. As described above, since the cartridge is removed after the storage tank 24 is emptied, leakage and disposal of the liquid developer 1 can be prevented. Here, it is desirable to use a coupling with a stopper mechanism so that the liquid developer 1 inside the pipe does not leak when the connection is released.

Next, the developer adjusting section 18 will be described. FIG. 2 is a top view as seen from the direction of arrow A in FIG. 1, with the lid 35 removed. FIG. 3 is an exploded perspective view of the developer adjusting section 18. Developer adjusting section 18
As shown in FIG. 3, an adjusting tank 30 as a storage unit storing the liquid developer 1 and a concentration detecting unit 32 for detecting the concentration of the liquid developer 1 stored in the adjusting tank 30.
And liquid amount detecting means 31 for detecting the liquid amount of liquid developer 1
A stirring means 33 for stirring the liquid developer 1; a transport pump 34 (see FIG. 1) for transporting the liquid developer 1 in a forward and reverse direction; and a lid 35 detachably provided on the upper part of the adjustment tank 30. And

First, the means 31 for detecting the amount of the liquid developer 1 in the adjusting tank 30 will be described. Developer adjusting section 18
Adjustment tank 30 is formed of a cylindrical opaque resin container, and a pair of transparent glass blocks 3
8a and 8b are provided. One glass block 38
A light emitting element 39 (see FIG. 2) is provided in a, and a light receiving unit 40 is provided in the other glass block 38b at a position facing the light emitting unit 39. The light emitting element 39 and the light receiving element 40 are located at positions corresponding to the lower limit (level A), the standard amount (level B), and the upper limit (level C) of the liquid developer 1 stored in the container, respectively. 39a,
b, c and the light receiving sections 40a, b, c are disposed to face each other. Then, the emitted light emitted from the light emitting section 39 reaches the inside of the adjustment tank 30 through one glass block 38a, and is received by the light receiving section 40 through the other glass block 38b.

As the liquid amount detecting means 31, for example, a light transmission type photoelectric switch can be used. The photoelectric switch includes a light emitting unit 39 including a light emitting element such as an LED,
The light receiving unit 40 includes a light receiving element such as a photodiode, and outputs a signal that is ON when light is blocked. When the liquid developer 1 does not exist on the optical path, the detection signal is not output because the amount of light transmitted from the light emitting unit 39 to the light receiving unit 40 is large. On the other hand, when the liquid developer 1 exists on the optical path, the light emitted from the light emitting unit 39 is blocked by the liquid developer 1 and the amount of transmitted light reaching the light receiving unit 40 decreases. That is, when the transmitted light amount reaching the light receiving unit 40 is small, it is determined that the liquid developer 1 is present, and the light receiving unit 40 outputs a detection signal.

Here, the threshold value of the light receiving section 40 is preset by a sensitivity adjusting trimmer or an auto tuning mechanism so as to output a detection signal when the amount of transmitted light is small. The threshold value is desirably set to an intermediate value between the maximum value and the minimum value of the amount of transmitted light. In addition,
The amount of transmitted light fluctuates near the threshold value due to the waving or bubbling of the liquid developer liquid level, and the detection signal output from the light receiving unit 40 becomes unstable, so that so-called chattering may occur. To prevent this chattering, for example, when detecting that the liquid developer 1 has fallen below the standard amount, a timer is set in the sequence program of the main controller, and a detection signal is output from the light receiving unit 40b continuously for a certain period of time. If not, a method of determining that the liquid developer does not exist may be considered. The set time of this timer is preferably 1 to 10 seconds, more preferably 3 seconds.
About 5 seconds is desirable.

As described above, the light emitting unit 39 and the light receiving unit 40
Is disposed at three positions corresponding to the liquid amount. That is, the lower limit (level A) includes the light emitting unit 39a and the light receiving unit 4
The light emitting unit 39b and the light receiving unit 40b are arranged at 0a, the standard amount (level B), and the light emitting unit 39c and the light receiving unit 40c are arranged at the upper limit amount (level C). This makes it possible to detect the level of the liquid amount of the liquid developer 1. This detection signal is input to a main controller (not shown).

The inner wall surface of the adjusting tank 30 is subjected to an oil-repellent treatment including the inner wall surfaces of the pair of glass blocks 38a and 38b so that the liquid developer 1 does not adhere to the inner wall surface. Therefore, a pair of glass blocks 38a, b
The amount of transmitted light does not decrease due to the effect of the liquid developer 1 attached to the inner wall surface of the light receiving unit 40, and malfunction of the light receiving unit 40 can be prevented. As the oil repellent treatment, a process of applying an oil repellent is performed. Examples of the oil repellent include, for example, ethylene tetrafluoride, ethylene trifluoride, vinylidene fluoride,
Polytetrafluoroethylene-6-fluoropropylene copolymer, IH
Pentadecafluorooctyl methacrylate, perfluorinated lauric acid, vinyl chloride, perfluorinated alcohol,
Perfluoroalkyl ester polymers, fluorine-containing hydroxy unsaturated esters and the like can be mentioned.

Next, the density detecting means 32 of the liquid developer 1 in the adjusting tank 30 will be described. Concentration detecting means 32
As shown in FIG. 3, a liquid carrying roller 42 rotatably held by a support plate 41 provided on the lower surface of the lid 35,
5 mainly includes an optical sensor 43 disposed on the upper surface and a rotation driving motor 44. Liquid carrying roller 42
Has a configuration in which an eccentric disk portion 42b and two equal-diameter disk portions 42a sandwiching the eccentric disk portion 42b from both sides and having a diameter larger than the diameter of the eccentric disk portion 42b are integrally formed. .

The liquid carrying roller 42 is partially immersed in the liquid developer 1 and rotated, so that the density detection target is formed in a circumferential recess formed at the step between the eccentric disk portion 42b and the two disk portions 42a. The liquid developer 1 is filled, and the liquid developer 1 is formed in a plurality of different film thicknesses corresponding to the concave portions. The light emitted from the light emitting portion of the optical sensor 43 passes through the detection hole 35e of the lid 35 and irradiates the developer liquid film formed in the concave portion. The light applied to the developer liquid film passes through the developer liquid film and is reflected on the side surface of the eccentric disk portion 42b. The reflected light is received by the light receiving section of the optical sensor 43, and an analog value corresponding to the intensity of the reflected light is output. While rotating the liquid carrying roller 42, the analog value of the optical sensor 43 continuously output with respect to the developer film of the plurality of thicknesses is integrated,
The liquid developer concentration is detected by comparing with a value obtained in advance.

In the density detecting means 32 having the above structure, an example has been described in which the liquid developer concentration is detected using the output detected by the reflection type optical sensor 43. Alternatively, a transmission type optical sensor may be used. In this case, the liquid carrying roller 42 composed of the two disk portions 42a and the eccentric disk portion 42b is formed of a transparent member such as glass or resin, and a light source is installed therein as a light emitting portion of the optical sensor, and A light receiving portion of an optical sensor that receives the transmitted light intensity from the light source is provided outside the roller. Thereby, the concentration of the liquid developer can be detected using the output detected by the transmission type optical sensor.

Next, the stirring means 33 of the liquid developer 1 in the adjustment tank 30 will be described. Inside the adjustment tank 30, a pair of stirring blades 33a as developer stirring means 33,
b is provided. These stirring blades 33a and 33b are attached to a drive shaft (not shown), and are rotated by a drive unit (not shown) to stir the liquid developer 1 in the adjustment tank 30. Note that a cylindrical container is used as the adjustment tank 30, and a pair of stirring blades 33a,
Since the distance between the tip of b and the inner peripheral surface of the container can be kept as small as possible, no liquid pool occurs. Thus, the liquid developer 1 can be uniformly agitated at a lower rotation speed as compared with a square or elliptical tank in which a liquid pool easily occurs.

The lid 35 has a hole 35 for toner supply.
a, carrier liquid supply hole 35b, photosensitive drum cleaning liquid recovery hole 35c, developing roller recovery hole 35d
Are provided, and toner and the like are supplied to the adjustment tank 30 through the respective holes.

Next, adjustment of the liquid amount and concentration of the liquid developer 1 in the developer adjusting section 18 will be described. FIG. 4 is a flowchart in the case where the concentration adjustment and the liquid amount adjustment of the developer adjustment unit 18 are performed.

Control is started by pressing the copy start button (S1). Then, the value i of the counter is reset to zero (S2). Next, the solid concentration of the liquid developer 1 in the developer adjusting section 18 is detected (S3). And
It is determined whether or not the solid concentration is equal to or higher than a specified concentration (S4).
If the solid concentration is equal to or higher than the specified concentration, the amount of the carrier is quantified from the carrier bottle 20, for example, several cc is supplied to lower the solid concentration (S5). When the carrier is replenished, the solid concentration in the developer adjusting section 18 may become non-uniform. Therefore, the transport pump 34 is stopped and the liquid developer 1 to the developing section 21 is stopped until the solid concentration becomes uniform by the stirring means 33. Supply is stopped (S6). Here, the supply of the liquid developer 1 to the developing unit 21 is usually stopped for about 10 seconds (S9 to be described later).
The amount applied to the developing roller 22 in the developing unit 21 is about 30 cc per minute. Therefore, the effect of stopping the supply of the liquid developer 1 does not occur immediately, and the developing operation is continued. Developing unit 21
After the supply of the liquid developer 1 to the printer is stopped, it is determined whether or not the numerical value i of the counter is smaller than a specified value (S7). Here, the specified value is set to, for example, 10. If the value i of the counter is smaller than the specified value, the value i of the counter is incremented by 1, and the process returns to the detection of the concentration of the liquid developer 1 (S3).
If the value i of the counter is not smaller than the specified value, it is determined that there is no carrier in the carrier bottle 20, and an alarm signal is issued to notify the user of replacement of the carrier bottle 20 (S8). Note that the time (10 seconds) for stopping the supply of the liquid developer 1 to the developing unit 21 changes depending on the viscosity or the supply amount of the toner, and the example of the present embodiment is an example and is not limited thereto. Not something. Further, the specified value (10) changes depending on the viscosity or ejection amount of the carrier, and the example of the present embodiment is an example, and is not limited to this value.

If it is determined in S4 whether or not the solid concentration is not less than the specified concentration, the supply of the liquid developer 1 to the developing unit 21 is started if it is determined that the concentration is not more than the specified concentration (S9). . Then, the value i of the counter is reset to zero (S10). Next, the liquid amount of the liquid developer 1 of the developer adjusting unit 18 is detected (S11), and it is determined whether the liquid amount is equal to or less than a specified amount (S12). The specified amount is based on the lower limit amount (level A). If it is determined that the liquid amount is equal to or less than the prescribed amount, a fixed amount of toner, for example, several cc, is supplied from the toner bottle 19 (S13). After toner supply,
It is determined whether the numerical value i of the counter is smaller than a specified value (S14). Here, the specified value is set to, for example, 10. If the value i of the counter is smaller than the prescribed value, the value i of the counter is incremented by 1 and the process returns to the detection of the liquid amount of the liquid developer 1 (S11). If the value i of the counter is not smaller than the specified value, it is determined that there is no toner in the toner bottle 19, and an alarm signal is issued to notify the user of replacement of the toner bottle 19 (S15). In addition,
The above specified value (10) changes according to the toner discharge amount or viscosity, and the example of the present embodiment is an example,
It is not limited to this numerical value.

If it is determined in S12 whether or not the liquid amount is equal to or less than the specified amount, if it is determined that the liquid amount is not equal to or less than the specified amount, it is determined whether or not the liquid amount is equal to or more than the upper limit (level C). If the liquid amount is not equal to or more than the upper limit (S16), it is next determined whether the copying machine body is in an idling state (S1).
7). When the liquid amount is equal to or more than the upper limit in S16, there is a possibility that the developer adjusting unit 18 overflows.
An alarm is issued to notify the user (S18). S
If it is not the idling state at 17, the control returns to S2 to continue the control, and if it is the idling state, the control is stopped (S19). Here, whether or not the copying machine body is in the idling state can be determined based on a control signal of a main controller (not shown) or the like.

[Modification 1] In the first embodiment,
An example in which three photoelectric switches each including a pair of light emitting units and a light receiving unit are used as the liquid amount detecting unit 31 of the liquid developer 1 has been described. However, one light emitting unit is provided alone and three light receiving units are provided. It is also possible to provide a configuration provided. FIG. 5 is an exploded perspective view of the developer adjusting section 18 according to the present modification.

One white lamp is provided in the adjustment tank 30 as the light emitting section 39, and the light receiving sections 40a, b, c are disposed in the three detection holes 30a, b, c formed in the adjustment tank 30. These three detection holes 30a, 30b, and 30c are formed at positions corresponding to the lower limit amount (level A), the standard amount (level B), and the upper limit amount (level C) of the liquid developer 1, respectively. Note that the inner wall surface of the adjustment tank 30 is
The oil-repellent treatment with the oil-repellent is performed on the detection surfaces a, b, and c.

When the liquid developer 1 is present at a position corresponding to the detection holes 30a, 30b, 30c, the light emitted from the light emitting section 39 is blocked by the liquid developer 1 and is transmitted to the light receiving sections 40a, 40b, 40c. Since the amount of light reaching is small, a signal indicating the presence of the liquid developer is output. On the other hand, when the liquid developer 1 does not exist in the portions corresponding to the detection holes 30a, 30b, and 30c, the light emitted from the light emitting unit 39 is not blocked by the liquid developer 1 and the light
Since the amount of light reaching 0a, b, and c increases, a signal indicating that there is no liquid developer is output. For example, the light receiving units 40a and 40b
When the detection signal is output from the light receiving unit 40c and the detection signal is not output from the light receiving unit 40c, it can be determined that the liquid developer 1 is the standard amount. In this way,
The liquid amount of the liquid developer 1 can be detected.

[Modification 2] Embodiment 1 and Modification 1
In the above description, a plurality of light receiving sections 40 are described as the liquid amount detecting means 31 of the liquid developer 1.
May be provided as a single unit. FIG.
(A) is a perspective view of a storage tank 30 according to the present modification. FIG. 6B is a diagram viewed from the direction of arrow B in FIG. 6A.

The liquid amount detecting means 31 according to this modification has a single white lamp as the light emitting section 39 provided in the adjusting tank 30, and a plurality of light receiving elements 40 a in the detecting holes 30 a formed in the storage tank 30. The light receiving element unit 40 is provided. The inner wall surface of the adjustment tank 30 is subjected to the oil repellent treatment with the oil repellent, including the detection surface of the light receiving element unit 40.

On the detection surface of the light receiving element unit 40, in the portion where the liquid developer 1 exists, the light emitted from the light emitting section 39 is blocked by the liquid developer 1 and the amount of light reaching the light receiving element 40a is small. A signal indicating that the liquid developer is present is output. On the other hand, in a portion of the detection surface where the liquid developer 1 does not exist, the amount of light emitted from the light emitting unit 39 reaching the light receiving element 40a without being blocked by the liquid developer 1 is increased. Output a signal. Thus, the liquid amount of the liquid developer 1 can be detected. For example, if eight light receiving elements 40a are provided inside, the liquid developer 1
Can be detected in eight stages, and the first embodiment can be used.
Further, the liquid amount can be detected more accurately than in the three stages of the first modification.

[Third Modification] In the first embodiment, the first modification, and the second modification, the liquid amount of the liquid developer 1 in the tank is detected by using the light transmission type sensor. The liquid amount of the liquid developer 1 can be detected using a displacement sensor. This is a method to which triangulation is applied, and detects a liquid developer liquid level by measuring a displacement of a distance between a sensor head and a liquid developer liquid surface. FIG. 7 is an explanatory diagram of a displacement sensor according to the present modification. The sensor head 45 includes a displacement sensor main circuit 46, a light emitting element 47,
It mainly includes a light projecting lens 48, a light receiving lens 49, and a light receiving device 50. As the light emitting element 47, a semiconductor laser is used. In addition, the light receiving device 50 can receive light in a predetermined range according to the height of the liquid developer liquid surface to which the light emitted from the light emitting element 47 and reflected on the liquid developer liquid surface can reach, and A specific light receiving position within the range can be detected. Specifically, a light position detection element (PSD) is used.

The light emitted from the light emitting element 47 driven by the displacement sensor main circuit 46 passes through the light projecting lens 48 and irradiates the liquid developer liquid surface 1a. The light reflected from the liquid developer liquid surface 1 a is received by the light receiving device 50 through the light receiving lens 49. Since the light receiving position also moves each time the level of the liquid developer liquid surface 1a changes, the amount of displacement up to the liquid surface, that is, the level of the liquid developer liquid surface 1a can be detected by detecting the light receiving position. . The detection signal output from the light receiving device 50 is amplified by the displacement sensor main circuit 46 and output as an analog signal (for example, 4 to 20 mA). This analog signal is input to an analog input unit of a main controller (not shown) and is internally converted into digital data (for example, 16-bit binary data). Thus, the main controller can determine the position of the liquid developer liquid surface 1a.

When the light receiving element unit of the second modification is used, the detection stage of the liquid level is physically limited by the number of the light receiving elements. In the displacement sensor according to the present modification, the sequence of the main controller is used. Depending on how the program is constructed, the liquid amount can be determined in more stages. The light emitting element 47 is not limited to the above-mentioned semiconductor laser,
An ED light source can also be used. Further, the light receiving device 50 is not limited to the above-described light position detecting element,
D) can also be used.

[Modification 4] In the first embodiment,
Although the configuration using the stirring blade as the stirring means 33 of the liquid developer 1 has been described, a configuration using a pump may be used. FIG. 8 is a perspective view of a storage tank 30 according to the present modification. The lower part of the storage tank 30 has an inverted conical shape. A circulation pipe 51 is provided so as to connect a suction port 52 provided at the lowermost part of the storage tank 30 and a discharge port 53 provided on an upper side surface. The circulation pipe 5
A circulation pump 54 is provided in the middle of 1, and sucks the liquid developer 1 from the suction port 52 and discharges the liquid developer 1 from the discharge port 53. Thus, by providing the circulation pipe 51 and circulating the liquid developer 1, the storage tank 30
The liquid developer 1 inside is redispersed and stirred.

[0067]

According to the present invention, after the liquid developer in the developing section is returned to the developer accommodating section and emptied, the developing section is separated from other portions of the developing device. Since the liquid developer is detached, there is an excellent effect that the liquid developer in the developing section can be prevented from being discarded or leaked during maintenance.

In particular, according to the third aspect of the present invention, the liquid developer supply means and the carrier liquid supply means replenish the liquid developer consumed by image formation to maintain an appropriate amount of the liquid developer. There is an excellent effect that the liquid developer whose partial concentration has changed can be adjusted to a predetermined concentration.

In particular, in the inventions of claims 4 and 5,
The concentration detecting means detects the solid content concentration of the liquid developer in the liquid developer container, and based on the detection result,
There is an excellent effect that the liquid developer concentration in the liquid developer container can be adjusted to a predetermined concentration.

In particular, in the fifth aspect of the present invention, the thin liquid developer layer is irradiated with light, and the amount of light reflected from the thin liquid developer layer or transmitted through the thin liquid developer layer. There is an excellent effect that the density can be detected by measuring the amount of transmitted light.

In particular, in the inventions according to claims 6, 7, 8 and 9, the collected liquid developer is redispersed to eliminate the agglomerated state of solids in the collected liquid developer, and Eliminate the sedimentation state. The recovered liquid developer recovered from the developing roller has a poor solid-state aggregating state, and thus has a poor resolving power when used as it is. However, in the present invention, since the agglomerated state is eliminated, the excellent resolving power can be prevented. There is.

In particular, claims 10, 11, 12, 13, 1
In the inventions of 4 and 15, the liquid developer liquid amount detecting means detects the liquid developer liquid amount in the liquid developer storage section, and based on the detection result, the liquid developer liquid in the liquid developer storage section. There is an excellent effect that the liquid amount can be adjusted to a predetermined liquid amount. Conventionally, a float sensor is used as a liquid amount sensor for a liquid developer. However, when the liquid developer has a high viscosity, an accurate liquid level cannot be detected, and a uniform liquid level is controlled. In some cases, it was not possible.
Therefore, the present invention has made it possible to accurately detect the liquid level and control the uniform liquid level.

In particular, according to the fourteenth aspect of the invention, the liquid developer in the liquid developer accommodating portion is adjusted so as to have a predetermined liquid amount and a predetermined concentration. There is an excellent effect that a developer can be supplied.

In particular, according to the fifteenth aspect, the inner surface of the liquid developer accommodating portion is subjected to oil repellent treatment to prevent the liquid developer from adhering to the inner surface. Thereby, there is an excellent effect that erroneous detection due to the liquid developer attached to the inner surface of the detecting portion of the liquid amount detecting means can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part of a wet image forming apparatus according to an embodiment.

FIG. 2 is a view taken in the direction of the arrow A in FIG. 1, showing a state in which a lid 35 is removed.

FIG. 3 is an exploded perspective view of a developer adjusting unit according to the embodiment.

FIG. 4 is a flowchart of concentration adjustment and liquid amount adjustment according to the embodiment.

FIG. 5 is an exploded perspective view of a developer adjustment unit for explaining a liquid amount detection unit according to a modification.

FIGS. 6A and 6B are exploded views of a developer adjustment unit for explaining a liquid amount detection unit according to another modification.

FIG. 7 is an explanatory diagram for explaining a liquid amount detection unit according to another modification.

FIG. 8 is a perspective view of a developer adjusting unit for describing a stirring unit according to another modification.

FIG. 9 is an explanatory view of a main part of a developing device of a wet image forming apparatus according to a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 photoconductor drum 13 developing unit 18 developer adjusting unit 19 toner bottle 20 carrier bottle 21 developing unit 22 developing roller 23 developer collecting unit 25 application roller 31 liquid amount detecting means 32 concentration detecting means 33 stirring means 34 transport pump 36 drain cock 37 Coupling 38a, b Glass block 39 Light emitting unit 40 Light receiving unit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Osamu Sato 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Noriyasu Takeuchi 1-3-6 Nakamagome, Ota-ku, Tokyo In Ricoh Co., Ltd. (72) Inventor Yusuke Takeda 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. BB72 CC04 CC12 CC22 CC32 CC41 CC62

Claims (15)

[Claims] 1. A wet image forming apparatus for developing an electrostatic latent image formed on an image carrier with a thin layer of liquid developer formed by a developing device and transferring the visualized image to a recording medium. Wherein the developing device comprises: a developing section provided with a developer carrier for supplying a thin liquid developer layer to the image carrier; and a developing device for removing and recovering the liquid developer on the developer carrier after development. A developer carrier cleaning section, and a liquid developer accommodating section capable of accommodating the liquid developer of the developing section, wherein at least the developing section is separable from other parts of the developing device. A wet image forming apparatus. 2. A liquid image forming apparatus according to claim 1, wherein said liquid developer is supplied from said liquid developer container to said developing unit, and said liquid developer is supplied from said developing unit to said liquid developer container. And a return unit. 3. The liquid image forming apparatus according to claim 1, wherein said liquid developer supply means supplies a new liquid developer to said liquid developer storage section, and supplies a new carrier liquid to said liquid developer storage section. A wet liquid image forming apparatus, comprising: a carrier liquid supply unit for supplying the collected liquid developer removed and collected by the developer carrier cleaning unit to the liquid developer storage unit. 4. A wet image forming apparatus according to claim 1, further comprising a density detecting means for detecting a density of the liquid developer stored in said liquid developer storing section. apparatus. 5. A wet image forming apparatus according to claim 4, wherein said density detecting means irradiates the thin liquid developer with light and measures reflected light or transmitted light of the light. Wet image forming apparatus. 6. A wet image forming apparatus according to claim 3, further comprising redispersing means for redispersing the recovered liquid developer in said liquid developer storage section. 7. A wet image forming apparatus according to claim 6, wherein said redispersing means circulates the liquid developer by a pump. 8. A wet image forming apparatus according to claim 6, wherein said re-dispersion means agitates the liquid developer by means of a stirring blade provided in said liquid developer storage. . 9. A wet image forming apparatus according to claim 8, wherein the inner shape of said liquid developer accommodating portion is formed to be slightly larger than the shape along the rotation orbit of the tip of said stirring blade. Wet image forming apparatus. 10. The method of claim 1, 2, 3, 4, 5, 6, 7, or 8.
Alternatively, in the wet image forming apparatus according to 9, the liquid image forming apparatus further includes a liquid amount detecting unit that detects a liquid amount of the liquid developer stored in the liquid developer storing unit. 11. A liquid image forming apparatus according to claim 10, wherein said liquid amount detecting means includes a light emitting element and a light receiving element which are arranged on a side wall of said liquid developer container so as to face each other. Wet image forming, wherein the presence or absence of liquid developer on the optical path is detected based on the amount of transmitted light of light emitted from the element and reaching the light receiving portion through the inside of the liquid developer accommodating portion. apparatus. 12. A liquid image forming apparatus according to claim 10, wherein said liquid amount detecting means irradiates light onto said liquid developer liquid surface, and said liquid developer liquid emitted from said light emitting element. A light receiving device capable of receiving light in a predetermined range according to the height of the liquid developer liquid surface to which light reflected by the surface can reach, and capable of detecting a specific light receiving position within the range; And a displacement of the liquid developer liquid surface is measured based on a light receiving position detected by the light receiving device. 13. A wet image forming apparatus according to claim 11, wherein said liquid amount detecting means detects at least a lower limit liquid amount, a standard liquid amount, and an upper limit liquid amount of the liquid developer. Forming equipment. 14. A liquid image forming apparatus according to claim 13, wherein when the liquid amount detecting means determines that the liquid developer liquid amount in the liquid developer accommodating section has fallen below a lower limit liquid amount, the liquid developing device performs the liquid developing operation. The liquid developer is supplied to the standard liquid amount by the developer supply means, and when the concentration detection means determines that the liquid developer concentration in the liquid developer storage section has exceeded the reference concentration, the carrier liquid supply means supplies the carrier. A wet image forming apparatus, which supplies a liquid. 15. The method according to claim 10, 11, 12, 13, or 14.
Wherein the inner surface of the liquid developer accommodating portion is subjected to an oil-repellent treatment.